The primary objective is to prepare the candidate to perform biomedical research as an independent investigator in child motor development and with clinical pediatric subject populations. The candidate has backgrounds in biomechanics and mathematics, specifically nonlinear dynamics. He is a research-oriented quantitative scientist who plans to apply his analytical abilities to study clinical biomedical and behavioral questions. The candidate will receive focused coursework and research training related to pediatric populations. He will enhance his education by receiving coursework in two core areas: 1) child development and neurophysiology, and 2) responsible conduct of research. Dr. Jeffrey French and Dr. Bradley Schaefer will mentor the candidate's research development and guide him in intensive research training for the study of child motor development, specifically infant postural control. The primary objective of this research is to increase understanding of postural control by examining the development of sitting posture in infancy. The development of early posture control remains poorly understood despite considerable therapeutic effort. Infants with developmental problems show some of their first delays in the acquisition of sitting, with subsequent problems developing adequate posture and movement control. Identifying the delay, determining the nature of the problem, and evaluating the effectiveness of treatment quickly is vital in the early part of an infant's life, since this is the time of greatest plasticity. Methods from nonlinear dynamics, which are increasingly being used to examine biological rhythms, will be used in this study to analyze and quantify developing postural control from center of pressure (COP) data during sitting. The PIs hypothesize that nonlinear tools will be sensitive enough to quantify the evolution of normal postural control over time in both typically developing infants and infants with benign congenital hypotonia. The proposed research will further understanding of the development of early postural control and provide better methods for evaluating treatment aimed at improving postural control. This information will lay the groundwork for future studies into the efficacy of treatment for infants and children with disorders of posture and movement.